1. Field of the Invention
The present invention relates to a lens installing/removing device for automatically installing and removing a photographing lens to and from a camera body.
2. Related Background Art
FIG. 1 is a perspective view illustrating a mount mechanism unit of the conventional photographing lens. A lens mount 3 is provided at the rear end of an interchangeable lens 2. This lens mount 3 includes bayonet pawls 3a, 3b, 3c formed outwards and connected to a body mount 10 (FIG. 2) which will be mentioned later.
Further, an impingement surface 3d is defined as a surface which impinges on the body mount 10. The impingement surface 3d serves as a reference position of the interchangeable lens 2 in the optical-axis direction when attaching the interchangeable lens 2 to the body.
A fitting part 3e is formed in a wall-like configuration adjacent to the impingement surface 3d around the optical axis. The fitting part 3e is fitted to a fitting part of the body mount 10 and serves as a reference surface for making the camera body 1 coincident with the optical axis of the interchangeable lens 2. Note that a major diameter of the fitting part 3d is larger than a major diameter of each of the bayonet pawls 3a-3c.
A protruded member of the body mount 10 is fitted in a reference notch 3f formed in the impingement surface 3d, the reference notch 3f serving as a reference for locating the camera body 1 and the interchangeable lens 2 in the direction around the optical axis.
A lens type signal groove 3g is intended to identify a type of lens between the camera body and the interchangeable lens 2, the system being such that a signal is distinguished depending on an existence and non-existence of this groove.
Incidentally, in the lens type signal groove 3g, a pin 18 projecting, though explained later, from the body mount 10 and movable in the optical axis direction drops down from the impingement surface 3d with a rotation about the optical axial due to attaching/detaching of the interchangeable lens 2. For this reason, an oblique surface 3i is formed from the impingement surface 3d to a bottom surface of the groove at least on the dropping side of the pin 18 at the end part of the lens type signal groove 3g in the peripheral direction around the optical axis.
Further, the above-mentioned reference notch 3f and the lens type signal groove 3g are disposed to differentiate a distance from an optical axis OP in the radial direction. Fitted in a hole 3h is an AF coupling 9 which will be stated later.
An aperture ring 4 is so mounted on the interchangeable lens 2 as to be rotatable about the optical axis. This aperture ring 4 is formed with a aperture transferring member 4a protruding in the radiant direction; and note that an aperture scale 4b is formed on the outer surface thereof. The interchangeable lens 2 is formed with an aperture index 2a. An unillustrated aperture mechanism incorporated into the interchangeable lens 2 is set to its aperture value by matching the aperture scale 4b with the aperture index 2a.
An aperture lever 5 is so provided at the rear end of the interchangeable lens 2 as to be substantially parallel with the optical axis and movable substantially in the vertical directions, the aperture lever 5 being biased downwards. This aperture lever 5 interlocks with the aperture ring 4 and the unillustrated aperture mechanism. When the aperture ring 4 is set to an open aperture value, the aperture lever 5 is in the uppermost position of the vertical stroke. Further, when set to the minimum aperture value, the aperture lever 5 is in the lowermost position. Still further, when set between the open aperture value and the minimum aperture value, the aperture lever 5 is in a proper mid-position of the vertical stroke.
Additionally, the aperture lever 5 is located in the uppermost position by an external manipulation resisting a biasing force thereof, whereby the unillustrated aperture mechanism set to the aperture value by use of the aperture ring 4 can be also subjected to an open-aperture variation. A so-called stop-down behavior is given thereto.
Hence, for instance, if the aperture ring 4 is set to the minimum aperture value, the unillustrated aperture mechanism is controllable to an arbitrary aperture value in a range from its open aperture value to the minimum aperture value by externally manipulating the aperture lever 5.
An open aperture value signal member 6 works to transfer the open aperture value provided on the internal part of the lens mount, the system being such that the open aperture value is distinguished in accordance with a position in the peripheral direction around the optical axis.
A lens contact-point unit 7 serves to relay a transmission of an electric signal between the camera body and the interchangeable lens. The lens contact-point unit 7 is provided with at least one or more contact points 7a. The respective contact points 7a are disposed in positions at equal distances from the optical axis within a plane vertical to the optical axis. Further, the respective contact points 7a are movable in the radiant direction from the optical axis and biased in such directions as to move away from the optical axis.
A focal distance signal member 8 is a member, provided inwardly of the lens mount 3, for distinguishing a focal distance, the system being such that the focal distance is distinguished depending on a position of this focal distance signal member 8. Therefore, a focal distance signal transmission mechanism (details will hereinafter be explained) provided inwardly of the camera body slides on the focal distance signal member 8 with a rotation about the optical axis due to the attaching/detaching of the interchangeable lens 2 in the same way as the pin with respect to the above-mentioned lens type signal groove 3g. A guide oblique surface 8a thereof is therefore provided at least on its sliding side.
An AF coupling shaft 9 fitted into a hole 3h is formed with a slotted coupling groove 9a in its outside end surface. This AF coupling shaft 9 is disposed so as not to protrude from at least the impingement surface 3d.
Then, a part or whole of an unillustrated lens system disposed within the interchangeable lens 2 is constructed to move in the optical axis direction by rotationally driving this AF coupling shaft 9 from outside.
FIG. 2 is a front elevation depicting a mount mechanism unit of the conventional camera body.
Referring to FIG. 2, the optical axis OP extends in the direction perpendicular to the sheet surface.
The body-side mount 10 is attached to the unillustrated to the camera body. In the body mount 10, bayonet pawls 10a, 10b, 10c engage with the bayonet pawls 3a-3c of the lens mount 3 in a state where the interchangeable lens 2 is installed. The interchangeable lens 2 is biased towards the camera body by pushing the bayonet pawls 3a-3c of the lens mount 3 through an unillustrated bayonet spring mechanism disposed on the rear side of the bayonet pawls 10a-10c.
An aperture interlocking member 11 is disposed around the body mount 10 and so provided as to be rotatable about the optical axis OP. In the state where the interchangeable lens 2 is installed, an impingement part 11a impinges on the aperture transferring member 4a of the aperture ring 4, with the result that the aperture interlocking member 11 and the aperture ring 4 integrally move. Aperture information of the interchangeable lens 2 is transferred to the side of the camera body.
An aperture control lever 12 movable in the vertical directions has an impingement part 12a which impinges on the aperture lever 5 in the state where the interchangeable lens 2 is installed, with the result that the aperture control lever 12 and the aperture lever 5 substantially integrally move. Namely, the aperture control lever 12 is constructed to control a position of the aperture lever 5.
An open aperture value signal interlocking member 13 is so provided as to be rotatable about the optical axis OP. This open aperture value signal interlocking member 13 has an impingement part 13a which impinges on an open aperture value signal member 6 in the installed state of the interchangeable lens 2. A position of the open aperture value signal member 6 in the peripheral direction around the optical axis is transferred to the side of the camera body 1, thus transferring an open aperture value thereof.
A body contact point unit 14 is constructed so that contact points 14a thereof are contact-conductive to the contact points 7a on the side of the lens, thus receiving and transmitting the electric signals between the body 1 and the interchangeable lens 2.
An AF driving shaft 15 is formed with a projection 15a on its end surface. The projection 15a fitted in the coupling groove 9a of the AF coupling shaft 9 on the side of the interchangeable lens 2, thereby transferring a rotary motion of the AF driving shaft 15 to the AF coupling shaft 9.
Note that this AF driving shaft 15 is so disposed in the position protruding from an impingement surface 10d of the body mount 10 as to be biased in the protruding direction.
A focal distance signal interlocking member 16 movable in the direction of the optical axis OP is biased outwards. This focal distance signal interlocking member 16 impinges on the focal distance signal member 8 in the installed state of the interchangeable lens 2. A focal distance of the interchangeable lens 2 is transferred to the camera body 1 in accordance with the position thereof in the optical axis direction.
A lens type signal interlocking member 17 movable in the direction of the optical axis OP is disposed to protrude from the impingement surface 10d and biased in the protruding direction. This lens type signal interlocking member 17 transmits a lens type signal by taking a protruded position and an unprotruded position from the impingement surface 10d depending on an existence and non-existence of the lens type signal groove 3g in the installed state of the interchangeable lens 2.
An installation/removal pin 18 is so provided on the body mount 10 as to be movable in the direction of the optical axis OP. The pin 18 is disposed to protrude from the impingement surface 10d and biased in the protruding direction. This installation/removal pin 18 is fitted in the reference notch 3f of the lens mount 3 in the installed state of the interchangeable lens 2, thus locking the rotation of the interchangeable lens 2 in the peripheral direction.
An installation/removal button 19 operates substantially integrally with the AF driving shaft 15 and the installation/removal pin 18. This installation/removal button 19 is capable of moving the AF driving shaft 15 and the installation/removal pin 18 to at least the unprotruded position from the impingement surface 10d by pushing them in the direction of the optical axis OP.
Given next is an explanation of a method of installing and removing the interchangeable lens 2 to and from the mount mechanism unit of the conventional camera body 1.
To start with, when installing the interchangeable lens 2, the bayonet pawl 3a of the interchangeable lens 2 is interposed between the bayonet pawls 10a and 10b of the body mount 10; the bayonet pawl 3b is interposed between the bayonet pawls 10b and 10c; and the bayonet pawl 3c is interposed between the bayonet pawls 10c and 10a. The lens mount 3 is inserted into the body mount 10, whereby the fitting part 3e is fitted in the fitting part 10e. Further, the impingement surface 3d impinges on the impingement surface 10d. At this moment, the AF driving shaft 15, the lens type signal interlocking member 17 and the installation/removal pin 18 are pushed by the impingement surface 3d and thereby moving to the unprotruded position from the impingement surface 10d.
In this state, the interchangeable lens 2 is rotated anticlockwise in FIG. 2. When the reference notch 3f comes to the position of the installation/removal pin 18, the pin 18 drops into the reference notch 3f, thereby locking the rotation in the peripheral direction.
At this time, the bayonet pawls 3a, 3b, 3c are substantially in such positions as to overlap with the bayonet pawls 10a, 10b, 10c. The interchangeable lens 2 is biased towards the camera body 1 by unillustrated bayonet springs disposed respectively between the bayonet pawls 3a, 10a, between the bayonet pawls 3b, 10b and between the bayonet pawls 3c, 10c. With this arrangement, the interchangeable lens 2 is held in a state of impinging on the impingement surface 10a of the camera body 1. A position of .the interchangeable lens 2 in the optical axis direction is thus determined.
Further, the fitting part 3e is fitted in the fitting part 10e, and hence the interchangeable lens 2 is made coincident with the optical axis OP of the camera body 1.
Engaged further and interlocked with each other 4 in the manner described above are the aperture ring and the aperture ring interlocking member 11, the aperture lever 5 and the aperture control lever 12, the open aperture value signal member 6 and the open aperture value signal interlocking member 13, the contact points 7a and the contact points 14a, the focal distance signal member 8 and the focal distance signal interlocking member 16, the AF coupling shaft 9 and the AF driving shaft 15, and the lens type signal groove 3g and the lens type signal interlocking member 17. The signals thereof are thus transmitted.
Next, the removable of the interchangeable lens 2 from the camera body 1 involves the steps of: initially pushing the installation/removal button 19 so as not to make the AF driving shaft 15 and the installation/removal pin 18 protrude from the impingement surface 10d; subsequently moving the bayonet pawls 3a, 3b, 3c to the positions between the bayonet pawls 10a, 10b and 10c by rotating the interchangeable lens 2 in the direction reverse to the direction when installed; and removing the interchangeable lens 2 by pulling it in the direction of the optical axis OP in those positions.
In the above-described conventional camera body and the mount mechanism unit of the interchangeable lens, the installation of the interchangeable lens 2 to the camera body 1 has hitherto required two steps of at the first onset, inserting the mount mechanism unit of the interchangeable lens 2 into the mount mechanism unit of the camera body 1; and thereafter rotating the interchangeable lens 2 about the optical axis.
For this reason, the installation of the interchangeable lens 2 takes a good deal of labors. Further, in some cases the interchangeable lens 2 is passed from one hand to the other according to the inserting and rotating operations depending on a weight and configuration of the interchangeable lens 2. There exists a possibility in which the interchangeable lens 2 may drop down.
Moreover, when fixing the interchangeable lens 2, in the case of a super telephoto lens, etc., to a tripod, the camera body 1 has to be rotated with respect to the interchangeable lens 2. The operating method differs from the ordinary one.
On the other hand, when detaching the interchangeable lens 2, there are needed the operations of rotating the interchangeable lens 2 while depressing the installation/removal buttons, and subsequently pulling it out of the camera body 1. There arises a problem, wherein more complicated operations than in the installing operation are demanded.